Recent Articles

A British patent is causing jitter in the GPS community, as the Ministry of Defence looking to satellite navigation vendors for royalties.

The patent, Modulation signals for a satellite navigation system, describes “a method for generating a subcarrier modulation signal for modulating a further signal, the method involving multiplexing or selectively combining portions for first and second subcarriers to produce the subcarrier modulation signal”.

The application carries a priority date of 2003.

According to this US report in Inside GNSS, the Ministry is seeking royalties from GPS receiver vendors via a subsidiary with the wonderfully Philip K Dickian name “Ploughshare Innovations”. The report says Ploughshare has been “approaching GPS manufacturers for roughly a year”.

While the patent has been granted in the UK, it is still running through the application process in America, and is currently still under review after a rejection notice.

One of the inventors named on the application, Tony Pratt, is on the Inside GNSS editorial advisory council.

Pratt, a consultant to the British government in the development of the Galileo satellite system, describes Galileo’s frequency and signal design in this 2003 article.

He and the other inventor named in the patent, John Owen, were members of the European Galileo Signal Task Force. According to Inside GNSS, unnamed sources are complaining that the MoD may have exploited Pratt’s insider status to craft the patent.

The task force’s work is designed to make Galileo and GPS Block III satellites (due for launch in 2014) compatible. The modulation scheme now claimed by the MoD was recommended for adoption by Europe and the USA back in 2006, by the GPS-Galileo Working Group on Interoperability and Compatibility. ®